Self closing bag

ABSTRACT

A bag comprising an envelope closed at one end by an end wall and delimiting a mouth at the other end, containing a charge capable of passing, for example under gravity, through said mouth, when said bag is in the inverted position, said envelope being shaped on itself at said mouth in order to close said bag. 
     At the opposite end to the end wall, the envelope is shaped on itself, in particular folded, to determine, without discontinuity: 
     an outer sleeve which is above the mouth when the bag is in the inverted position; 
     at least one inner closure fold; 
     a neck inside which the inner closure fold is located; 
     and at least one outer closure fold closing said neck.

This application is a 371 of PCT/FR99/00768 filed Apr. 1, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to a bag for packaging or conditioning acharge of one or more products, which may, for example, flow out undergravity, whether this be a solid particulate product, for example apowder, or a single object or multiple objects packed loose.

DESCRIPTION OF THE PRIOR ART

More specifically, the invention involves bags which in general comprisean envelope closed at one end by an end wall and at the other enddelimiting a mouth which, when opened, allows the charge to pass or passthrough, the charge flowing for example under gravity when said bag isin the inverted position. Furthermore, the envelope is shaped on itself,especially folded, at the mouth in order to close this bag.

For a specific application, the applicant company is interested in a bagas previously defined, which meets the following requirements:

that it can be opened with just one hand, by a simple gesture, withoutthe operator or handler's hand coming into contact with the inside orthe edge of the mouth, particularly in order to avoid any contaminationof the latter;

and, when in the inverted and unopened position, that it can cloneitself under the effect of the charge of product contained in the bag,that is to say oppose the opening of the mouth under the effect of thissame charge.

SUMMARY OF THE INVENTION

Having tried out various configurations or foldings of the bag envelope,at its mouth, the applicant company has discovered that the followingshaping, obtained without discontinuity of the envelope and without anyattached parts, sheets or walls, met the aforementioned requirements.This shaping, obtained by folding or folding over the envelope onitself, comprises:

an outer sleeve which is above its mouth when said bag is in theinverted position, that is to say with its mouth lowermost;

at least one inner closure fold;

a neck inside which the inner closure fold is located;

and at least one outer closure fold closing said neck.

Through various tests, the applicant company has also discovered thatsuch a shaping additionally made it possible to obtain relative sealingat the closure of the mouth of the bag, particularly when this bag isplaced inside another bag, itself on the outside, and when the two bags,the inner one and the outer one, are under partial vacuum.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described with reference to the appendeddrawing, in which:

FIG. 1 depicts a use-once assembly intended, for example, to be coupledto a device for allowing communication with a fixed chamber, thisassembly comprising an inner bag according to the invention;

FIGS. 2 to 7 respectively depict the various steps involved in shapingthe envelope of the bag, which envelope is filled with a charge (notdepicted), in order to culminate in the shaping depicted in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with FIG. 1, there is depicted a use-once assemblyintended to be coupled to a device for allowing communication with afixed chamber, for example a clean or sterile room.

This assembly generally comprises:

an outer bag 10 which may be under partial vacuum and has a flexiblewall;

a member 11 for shutting off the outer bag 10, comprising and this isnot depicted, a removable shutter element with a sealing gasket;

and an inner bag 1 which can also be under vacuum, placed inside theouter bag 10, containing a charge 12 of a product or loose objects.

The bag 1 comprises an envelope 2 which is closed at one end by an endwall 3 and at the other end delimits a mouth 4 which is closed thanks tothe shaping of the envelope 2 as described hereafter, at this mouth.

As FIG. 1 shows, this shaping determines, without discontinuity ofmaterial or of the wall, but also without any attached sheets or otherwalls:

an outer sleeve 6 located below mouth 4 when the bag is in a position,such that mouth 4 is uppermost;

at least one inner closure fold 7;

a neck 8 inside which the inner closure fold 7 is located;

and at least one outer closure fold 9 closing said neck 8.

As FIGS. 2 to 7 show, this shaping is obtained as follows.

According to FIG. 2, the starting point is an envelope 2 with a closedend 3, in the shape of a bucket, determining an opening 4 with an upperand peripheral edge 2 a.

As FIG. 3 shows, the edges 2 a of the opening 4 of the bag being formedare folded outward then inward in order to obtain a turned-up flap 2 bextended by an outer envelope 2 c.

In accordance with FIGS. 4 and 5, the parallel edges 2 d of the flap 2 bare brought together and folded using any appropriate fold, to form atleast one fold 7 for internally closing the bag.

As shown by FIG. 6, it is the outer envelope 2 c which makes it possibleto obtain the neck 8 inside which the inner closure fold 7 is located.

In accordance with FIGS. 6 and 7, the parallel edges 2 e of the outerenvelope 2 c are folded to form at least one fold 9 for externallyclosing the bag.

If necessary, the inner closure fold 7 and the outer closure fold 9 maybe supplemented, in order to keep them sealed, by any appropriatewelding, bonding or clamping method or means, generally indicated as 20in FIG. 1.

Of course, the envelope 2 is made of an appropriate material, forexample any single or compound plastic, which intrinsically has theflexibility and sealing required for the application in question

Thanks to the shaping according to the invention, and when the bag 1 isin the inverted position, the charge 12 tends to dilate the bag 2 andthe sleeve 6. Because of its double thickness, the latter opposes thisdilation and especially prevents the unfolding of the fold 7 under theeffect of the charge.

With the shaping described earlier, by pulling on the outer fold 9 withjust one hand, the entire envelope 2 is unfolded above the mouth 4without making any openings at this mouth, for example by cutting ortearing, and therefore without being liable to contaminate the inside ofthe bag 1 on account of the manipulation for opening the latter.

What is claimed is:
 1. A method of forming a bag for containing acharge, said method comprising the steps of: (a) forming an envelopehaving a closed first end and an open second end having peripheral edgesand being located apart from the first end and through which the chargemay pass, the open second end having peripheral edges; (b) shaping theenvelope at the open second end to form a closure to the bag byperforming the following steps: folding the peripheral edges of the opensecond end outward in a direction away from each other and away from theopen second end; folding the peripheral edges of the open second end,previously folded outward, inward in a direction toward each other andtoward the open second end to form a turned-up flap and an outerenvelope located proximal thereto, the turned-up flap having proximallylocated parallel edges and the outer envelope having proximally locatedparallel edges; forming an inner closure fold for internally closing thebag by folding the proximally located parallel edges of the turned-upflap; and forming an outer closure for externally closing the bag byfolding the proximally located parallel edges of the outer envelope.